Noise is a common customer complaint within the interior compartment of a vehicle. The firings of cylinders in an internal combustion engine of a vehicle may generate torsional vibrations thus causing noise heard by the user of the vehicle. These periodic firings generate torsional vibrations as a fixed order of the engine rpm. An excitation sweep starting at idle up to the maximum engine speed is measured and graphically depicted. Various multiple degrees of freedom have several eigenforms per its inertia, torsional rates, and dampening. Each eigenform has a certain frequency, vibration shape, and resonant application. Systems not having dampers on the propshaft exhibit higher frequency versus amplification on a system with amplifying eigenmode (resonance) not having dampers on the propshaft.
The noise and vibration of an amplified eigenmode in resonance heard by the user of the vehicle is significantly reduced through the use of torsional propshaft dampers. The propshaft damper works as an added single degree of freedom system tuned to the problem eigenform of the driveline. FIG. 2 illustrates the graph 30 showing frequency versus amplification of the reduction of torsional resonant vibration when using a damper at line 34 and not having a damper at line 32. Line 34 is an example of the frequency versus amplification of the present invention.
Several known propshaft dampers exist such as a damper having rotating support pins and being pressed onto a flange/shaft OD. Other dampers includes a damper having a track but assembled with a rubber coupling and being pressed to an OD of a flange protrusion which accommodates a center sleeve. Other dampers include a damper having a rubber coupling or a propshaft damper pressed to a minimum shaft flange accommodated into a cv-joint. Even further, these dampers all require the user of a bolt or other fastener for assembly. The dampers of the prior art are frequently prohibitively expensive to manufacture when assembled between a u/cv-joint and a transmission flange because of the number of components required, the weight and assembly costs. As such, there exists a need in the art to provide a propshaft damper producing effective results at a lower cost.